1. Field of the Invention
The present invention relates to reproduction of sound in multichannel systems generically known as “surround-sound” systems and more specifically to the application of psychoacoustic and acoustic principles in the design of a multi-driver single enclosure loudspeaker system for enhancing center channel sound localization and intelligibility from a single enclosure “surround-sound” loudspeaker system located in front of a listening space.
2. Discussion of the Prior Art
Surround-sound or home theater loudspeaker systems are configured for use with standardized home theater audio systems which include a plurality of playback channels, each typically served by an amplifier and a loudspeaker. In Dolby™ home theater audio playback systems, there are typically five channels of substantially full range material plus a subwoofer channel configured to reproduce band-limited low frequency material. The five substantially full range channels in a Dolby Digital 5.1™ system are typically, center, left front, right front, left surround and right surround. The center channel is typically positioned in a home theater system directly over or under the video display and that channel used by content creators for most of the dialog, which has the desirable effect of making reproduced dialog sound as if it were emanating from the display.
Unfortunately, when typical surround sound loudspeaker systems are installed in listener's homes, setup problems are encountered and many users struggle with speaker placement, component connections and related complications. In response, many listeners have turned to “soundbar” style home theater loudspeaker systems which incorporate at least left, center and right channels into a single enclosure configured for use near the user's video display.
These soundbar style single enclosure loudspeaker systems are simpler to install and connect, but provide unsatisfactory performance for listeners who listen from listening positions arrayed in a listening space. There is often only one position directly in front of the center of the soundbar which provides acceptable center-channel performance, meaning that the listener can actually hear dialog, localize the center channel and the dialog as appearing to emanate from the display and appreciate a high fidelity, natural dynamic quality to that portion of the program material rendered in the center channel. Listeners positioned elsewhere in the listening space must suffer with significantly poorer center channel dialog intelligibility and localization, and those other listeners usually notice that the center channel sound they hear is difficult to understand, not easy to localize, and distorted or compressed, especially if the audio program material is dynamic (e.g., with explosions or other loud effects).
The typical soundbar loudspeaker (by definition, multi-element, single-enclosure) thus does a very poor job of reproducing center channel program material for those poorly positioned listeners, whether discrete within a multichannel mix (such as Dolby Digital 5.1) or derived from a 2-channel mixdown via any appropriate means (such as SRS or Dolby ProLogic algorithms), and so experience poor intelligibility of dialog, a lack of overall clarity, unnatural timbre and dynamics of music or other effects and this poor performance is experienced and appreciated for most of the listener seating and viewing locations in typical (domestic) home theater environments.
There is a need, therefore, for a loudspeaker system and method for reproducing home theater audio program material and especially center channel dialog material for listeners arrayed within a realistically large seating space, where dialog for all listeners is intelligible, natural sounding and localized to the center of the loudspeaker, regardless of each listener's location relative to the loudspeaker within the listening space.